1. Field of the Invention
This invention relates to an inkjet printing device and an inkjet printing method which enable ejection recovery of a print head while reducing the ink consumption and the amount of paper waste.
2. Description of the Related Art
In inkjet printing techniques, the ejection recovery operation is known for solution of disadvantageous problems of deterioration in printing quality and the like which result from an ejection failure caused by clogging in a nozzle in a print head or the like or from an increase in ink concentration caused by evaporation of water from a nozzle. In the ejection recovery operation, ink is ejected from the print head for removing the ink of increased viscosity from within the nozzle. There are two techniques for this purpose, the technique of ejecting ink to an area other than a print medium, for example, to the inside of the cap or the like, and the technique of ejecting ink on a print medium (on-paper preliminary ejection), for example, when a plurality of images are continuously printed. In turn, the on-paper preliminary ejection includes a technique of ejecting ink between a plurality of print images to be printed on the print medium (between-image preliminary ejection), and a technique of ejecting ink within a print image to be printed (in-image preliminary ejection). Japanese Patent Laid-Open No. 2006-076247 describes the technique of monitoring at all times or counting the presence/absence of ink ejection from each nozzle within a certain time period to determine the necessity of the in-image preliminary ejection for each of the target nozzles and performing both the between-image preliminary ejection and the in-image preliminary ejection for the purpose of providing desired printing quality.